In the related art, a device is known, which is configured to determine whether to execute a drive assist using a TTC which is a time to collision between a host vehicle and an obstacle. For example, in Patent Literature 1, it is disclosed that the pre-crash safety (PCS) control is executed in a case where a possibility of collision calculated based on the TTC between a host vehicle and a target object (an obstacle or the like) exceeds a reference value.